Video
cards (video boards / video display boards / graphics cards / graphics
adapter) is a physical hardware circuit board(s) which connects to
the Motherboard. When the video card is connected to a monitor it
serves as the visual link between you and your computer, allowing
you to view and manage your computers software data.

Typical
Video Card Connectors

VGA (Video Graphics Adapter)
use to connect analog monitors

DVI
(Digital Video Interface)
use to connect digital monitors

HDMI (High Definition Multimedia Interface)

Display Port

Video Cards are usually

Built-in
to the motherboard (Integrated Video Card)

PCI-e (The fastest and the most expensive)

AGP (Extremely Fast)

PCI (Fast)

ISA (Cheap and Slow)

Expansion
Bus Chart:

Type
of Bus

Bits
Wide

Transfer
Speed

ISA

8 bit

2.38MB/s

ISA

16 bit

8MB/s

PCI (Client)

32 bit

133MB/s

PCI (Server)

64 bit

266MB/s

AGP 1x

32 bit

266MB/s

AGP 2x

32 bit

533MB/s

AGP 4x

32 bit

1,066MB/s

AGP 8x

32 bit

2,133MB/s

AGP 8x
(high-end)

64 bit

4,266MB/s

PCI-e

Lane
Widths

Peak
unidirectional bandwidth

Peak
full duplex bandwidth

x1

250MB/s

500MB/s

x2

500MB/s

1GB/s

x4

1GB/s

2GB/s

x8

2GB/s

4GB/s

x16

4GB/s

8GB/s

x32 (new)

8GB/s

16GB/s

Video
Memory

32MB is a typical Video Memory if you are into gaming you will need
more or you’re going to run the new Vista OS you are going to
need at least 128MB
If your a gamer 512MB or more is needed to play those complex games

Direct
X - is a collection of API’s for handling tasks related
to Multimedia and Microsoft Platforms.

Types
of Video Memory

Speed

VRAM

Fast (Obsolete)

WRAM

Fast (Obsolete)

SDRAM

Fast (Low
End PCI/AGP)

SGRAM

Very Fast
(PCI/AGP)

DDR-SDRAM

Very Fast
(High End PCI/AGP)

G-DDR2-SDRAM

Extremely
Fast (High End AGP/PCI-e)

G-DDR3-SDRAM

Extremely
Fast (High End AGP/PCI-e)

G-DDR4-SDRAM

Extremely
Fast (High End AGP/PCI-e)

G-DDR5-SDRAM

The fastest video card
(High End AGP/PCI-e)

VGA vs.
SVGA vs. XGA

All video cards use VGA routines to generate basic display to interact
with a PCs system BIOS. Then, any advancement on these routines with
no universal standard to speak about, to generate display and color
above 640x480 with 16 colors is considered SVGA or XGA. I believe
I can state without exception all video cards sold in nearly a decade
would be considered SVGA or XGA (LCD and Laptops), capable of displaying
a larger realm of color and resolution than basic VGA or 640x480 -
16 colors.

Video Memory vs. Video Speed

One of the most misunderstood components of a video card is the Video
Memory. Video memory does not equate to Video speed. Video speed is
determined by two major factors: the chipset on the video card and
the I/O slot holding the video card, (ISA. PCI, AGP, PCI-e). Video
memory only determines the ability to display a certain color depth
and resolution, such as 800x600-16million colors. There exists a mathematical
formula to determine the required amount of memory on a video card
to display varying degrees of color and resolutions, but let us suffice
to say that a four (4MB) video card can display 1024x768-16million
colors all that is required to work with photographic 2D images. Since
it is rare today to find any video cards with less than 4MB/s of memory,
this is not really much of an issue.